Effect of Eu2O3 nanoparticles on structural and superconducting properties in Bi(Pb)-2223 high temperature superconductor / Nurbaisyatul Ermiza Suhaimi

The structural and superconducting properties of Bi1.6Pb0.4Sr2Ca2Cu3Oy (Bi(Pb)-2223) high temperature superconductor synthesized through solid-state reaction method with doping and addition of Eu2O3 nanoparticles have been studied. The samples of Bi1.6Pb0.4Sr2(Ca2-xEux)Cu3Oy (0.000 ≤ x ≤ 0.100) for both high and low density together with Bi1.6Pb0.4Sr2Ca2Cu3Oy + xEu2O3 (0.0 ≤ x ≤ 1.0) have been successfully prepared. In order to produce a low density sample, crystalline sucrose was added during pelletization process and burned at 400oC for two hours. The structural of the samples were studied using X-ray diffraction (XRD) analysis while the microstructural is investigate using Field-Emission Scanning Electron Microscopy (FESEM), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDX) spectroscopy for elemental analysis. The electrical and magnetic properties of the superconductor were investigated using the four-point probe method and Alternating Current Susceptibility (ACS), respectively. Substitution of Eu2O3 nanoparticles in both high and low density favours the growth of Bi-2212 phases more compared to addition samples. The substitution of Eu2O3 nanoparticles resulted in a change of crystallographic structure from tetragonal to orthorhombic in low density samples while the change occurred for x > 0.0025 for high density samples. However, the crystal structure remains unchanged in Bi(Pb)-2223 samples with addition Eu2O3 nanoparticles. As determined by FESEM and SEM investigations, the surface morphology of the microstructures degraded and the porosity increased towards the Eu2O3 nanoparticles concentration, which resulted in the degradation of the superconducting properties. However, low density samples adding with Eu2O3 nanoparticles showed better grain alignment compared to the substitution samples. From the resistivity measurement, the R–T curve showed a smooth resistivity curve for all samples that correspond to Bi-2223 phase one-step transition. Apparently, the Tc value of the high density Bi(Pb)-2223 was determined at 89 K while the Tc value is higher for low density sample at 99 K for both Eu-free samples. However, the Tc value decreases when substituted with Eu2O3 nanoparticles for both high and low density series. Sample with 0.2 wt% Eu2O3 nanoparticles yields the highest Tc zero at 89 K for addition series. Meanwhile, when the concentration of Eu2O3 nanoparticles increased, so did the Jc value. The Jc values of the samples with added Eu2O3 nanoparticles were found to increase compared to those of the substitution samples. The highest Jc enhancement was obtained for x = 0.2 wt% sample with 7.29 A/cm2. The AC susceptibility measurement shows that intragranular peak, Tpm were observed in Bi(Pb)2223 substituted samples. The optimum sample for high and low density doped with Eu2O3 nanoparticles are found at x = 0.0025 while for addition sample is found at x = 0.2 wt%. The present results show that addition sample yields greater value and performance compared to substitution samples. Overall, it can be concluded that doping and adding a small amount of Eu2O3 nanoparticles can enhance the structural and superconducting properties of the BSCCO system.